The Ochoa series has very few fossils, probably because conditions grew much less favorable for life during the last of the Permian, when many marine invertebrates, the kinds preserved in earlier strata, were going extinct.
Cuvier did not think that these transitions were the result of divinely mandated catastrophes; and although he did not fully understand the mechanisms behind them, he hypothesized that the animals that succeeded those of earlier strata may have migrated in from elsewhere as the environments changed.
Heteronectes is a related, and very similar fossil from slightly earlier strata of France.
If the chordates radiated before the Cambrian as molecular analyses suggest, there are only rather dubious chordate fossils in earlier strata.
This dissertation interprets a body of textual material from the earliest stratum of Chinese formulations of "buddha-nature" thinking.
Rather, you could think of it as springing from two sources, each of which flows back to the earliest stratum of the country's existence.
In this early stratum of his literary activity he was attracting attention as a writer of historical drama (the three Henry VI plays) and tragedy (the blood-soaked Titus Andronicus).
Probably, to begin with, the Muses were one of those vague collections of deities, undifferentiated within the group, which are characteristic of certain, probably early, strata of Greek religion.
In the earliest strata of texts reliably attributed to Bodhidharma and other early Chan teachers (see Broughton 1999), we find Bodhidharma claiming that there are two points of entry to Buddhism: via li, an "informing impetus" or "principle"; and via xing, "practice".
Already in the earliest strata of the canonical literature we find a tripartite model of cognition in which a clear distinction is made between the phenomenal world, its mode of apprehension, and the specific type of consciousness by which it is apprehended.
